Revert change 23636 as it is causing issues on dartium. Will resubmit after investigating the darti…

runtime/vm/object.cc

Index: runtime/vm/object.cc
===================================================================
--- runtime/vm/object.cc	(revision 23640)
+++ runtime/vm/object.cc	(working copy)
@@ -5456,7 +5456,8 @@
   static uint8_t* Reallocate(uint8_t* ptr,
                              intptr_t old_size,
                              intptr_t new_size) {
-    return Utils::Realloc(ptr, old_size, new_size);
+    void* new_ptr = ::realloc(reinterpret_cast<void*>(ptr), new_size);
+    return reinterpret_cast<uint8_t*>(new_ptr);
   }
 
   static const int kInitialTokenCount = 32;